Pipette



L. V. GUILD Jan. 4, 1955 PIPETTE Filed Aug. 28, 1952 United States Patent O "ce PIPE'ITE Lloyd V. Guild, Library, Pa. Application August 28, 1952, Serial No. 306,870 2 Claims. (Cl. 23-292) This invention relates to new and useful improvements in pipettes for analyzing gases and the present application is a continuation-in-part of my copending application Serial No. 81,516, filed March 15, 1949, now U. S. Letters Patent No. 2,163,082, issued October 7, 1952.

It is among the objects of my invention to provide a double walled pipette having a conical shape re-entrant base and a conical shape top which is completely filled with glass tubes to provide maximum contact of the gases in their passage through the pipette whereby the number of passes of gases and the time of making analyses is greatly reduced. The invention will become more apparent from a consideration of the accompanying drawing constituting a part hereof, in which like reference characters designate like parts, and in which Fig. 1 is a side elevational view partially in cross section of a pipette embodying the principles of this in vention;

Fig. 2 is a similar view of a rubber plug; and Fig. 3 is a front elevational view of a modified form of pipette.

With reference to the several figures of the drawing, the numeral 1 designates a glass vessel or pipette of cylindrical shape having a re-entrant bottom wall of conical shape designated by the numeral 2 and constricted at the top to form a narrow neck or tube 3. An inlet 4 is provided at the shoulder portion 5 of the pipette and an inner cylindrical wall 6 terminates at 7 adjacent the bottom of the pipette to provide a space for communication of the inner chamber formed by the cylindrical wall 6 and the outer wall 1 of the pipette. The inner wall 6 is formed integral with the outer wall as shown at 8. The top of the pipette is of conical shape as shown at 9, being substantially the same inclination as the shape of the re-entrant bottom tube for the purpose of housing a series of glass tubes 10, which tubes may be made of material commercially known as Saran which eliminates breakage of the tubes. A rubber cone 11, Fig. 2, may be inserted in the re-entrant bottom tube of the pipette as a support. The upper cone 9 prevents the trapping of gas when drawn through the orifice 12.

In use the pipette 1 is completely filled with absorbing solutions with the inner chamber full to the liquid level, designated by the numeral 13, of the orifice 12, and the outer chamber constituted by the outer and inner walls 1 and 6 of the pipette is filled to the level indicated by the reference numeral 14. The fluid is charged through the inlet 4 of the pipette.

As the gas to be analyzed is introduced through the orifice 12 the liquid level in the inner chamber 12 and the liquid level in the outer chamber, designated by the numeral 14, rises. The solution wets the tubes which brings about good contact with the gases and after adsoriagion the liquid level is restored to the level indicated at By the employment of the cone shaped re-entrant bottom and top of the pipette the inner tubes 10 com- 2,698,778 Patented Jan. 4, 1955 pletely fill the pipette to assure maximum contact with e gases. This reduces the space of the pipette to a minimum and decreases the number of passes of the gases and the time of making an analysis and results in a highly efiicient pipette for general laboratory purposes.

In the double barrel type pipette shown in Fig. 3 the contact tubes 10 completely fill the pipette 15 with contact surface the same as in the concentric type of Fig. 1. The fluid, however, is charged into pipette 16 and communicates with pipette 15 through the connection 17.

Instead of the re-entrant bottom 2 as in the structure of Fig. 1, pipette 15 is provided with a shoulder flange 21 on which is placed a conical member 22 that displaces the glass tubes 10 into the cone shaped upper chamber The construction of Fig. 3 does not require the partition wall 7 and is therefore easier to make and requires fewer passes in making the analysis.

Although several embodiments of the invention have been herein illustrated and described, it will be evident to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth.

I claim:

1. In apparatus for analyzing gas mixtures, a pipette comprising a cylindrical container having a conical base and a conical top, a cylindrical partition extending inwardly from the base of said conical top to substantially the bottom of the container forming a seal with the outer wall at the top thereof and being open at the bottom portion thereof, and a plurality of glass rods of equal lengths disposed in and filling the chamber formed by the cylindrical partition, said rods resting on the conical face of the bottom portion and extending into the conical upper portion, said cylindrical container having a constricted portion at the top with a relatively small gas flow passage and having an outlet communicating with the space formed by the double wall of the container.

2. Ina pipette for analyzing gas mixtures, the combination with a cylindrical vessel having a conical shaped re-entrant bottom and a conical shaped top of complementary size and shape and having a cylindrical wall spaced from the outer wall of the vessel integrally formed with the conical top wall by being joined circumferentially around the base of said conical top wall and extending downwardly in spaced relation with the bottom wall of the vessel, a plurality of tubes of equal length completely filling the space within the inner wall of the vessel and resting upon the re-entrant conical bottom of the vessel, said tubes extending upwardly to substantially contact the upper conical wall to provide a minimum space above the conical top of the vessel, said vessel having a constricted portion at the top thereof constituting a gas flow inlet to the chamber formed by the inner cylindrical wall and having a fluid inlet connection provided at the top of the shoulder from which the conical upper wall extends on said vessel.

References Cited in the file of this patent FOREIGN PATENTS France Apr. 19, 1926 France Nov. -.18, 1930 (1st addition No. 37,810.)

OTHER REFERENCES Modern Laboratory Appliances, 526, 536. Fisher Scientific Co.,

pages 5 20, Pittsburgh,

Catalog Co., Chicago, Illinois. 

1. IN APPARATUS FOR ANALYZING GAS MIXTURES, A PIPETTE COMPRISING A CYLINDRICAL CONTAINER HAVING A CONICAL BASE AND A CONICAL TOP, A CYLINDRICAL PARTITION EXTENDING INWARDLY FROM THE BASE OF SAID CONICAL TOP TO SUBSTANTIALLY THE BOTTOM OF THE CONTAINER FORMING A SEAL WITH THE OUTER WALL AT THE TOP THEREOF AND BEING OPEN AT THE BOTTOM PORTION THEROF, A PLURALITY OF GLASS RODS OF EQUAL LENGTHS DISPOSED IN SAID FILLING THE CHAMBER FORMED BY THE CY- 